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-   -   Convert Thunderbird from 3/4 rig to ful (http://www.briontoss.com/spartalk/showthread.php?t=166)

rodangus88 03-14-2006 09:53 AM

Convert Thunderbird from 3/4 rig to ful
 
I'd like to throw some sail up front on my 26' Thinderbird by converting it to a full rig. It has a very heavy duty mast already. Anyone have any suggestions or ideas about the best way to do this. Class rules don't apply here. best, Rod.

Unregistered 03-14-2006 11:16 AM

why fuss with the rig?
 
Hi there,

Not to pooh-pooh your idea, but changing from the 3/4 rig to a masthead rig here would involve a re-rig to get those uppers up to the top of the mast and to remove the jumpers. Plus, I think you'd lose alot of the flexability of the rig as it is (or as it usually is - I'm not sure if what you have now conforms to the plans ...) which you need to take advantage of that big main. Then, the foretriangle here isn't very big to begin with - the class plan shows two sails - a 106sf working jib and a 168sf genoa - have you tried this larger sail? That might be alot cheaper and faster than mussing up the rig as designed.

Best,


Jason

rodangus88 03-14-2006 11:24 AM

not quite masthead rig...
 
Thanks Jason. What I actually want to do is just fly a much bigger spinnaker from the top and just leaving alone all rigging for the fore-sails.
So I'm thinking about just running an extra shroud down each side from top to deck, through the spreaders, to give the rig additional lateral strenth. Rod.

Brion Toss 03-17-2006 06:38 AM

Oy
 
Hello,
This could be a huge can of variable, the kind that lead to mast failures ó I've seen more than one resulting from exactly this plan. Your rig is designed for certain forces. I don't know precisely what those forces are, as it sounds like you don't have a standard stick, but you need to know, before moving ahead. If we were doing this, we'd design a rig that could do what you want, and then see how it might compare with the changes you have in mind. But I can tell you now that those new uppers would, at the very least, put more compression load on that mast, a lot more. And that without a jibstay, which would add even more compression, you will likely have an unstable masthead.
It is possible that your changes could work, but please do the design work first.
Fair leads,
Brion Toss


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